In 2001, the movie Iris strove to illustrate the life of Iris Murdoch, based on a memoir by Murdoch's husband, John Bayley. The film won awards, but critics complained that it dwelt on the saddest and least productive period in Murdoch's life, when she struggled with Alzheimer's disease. Murdoch's own letters here in Living on Paper offer a more accurate portrait, both of a great literary and academic figure and of the woman behind the reputation.

In 2001, the movie Iris strove to illustrate the life of Iris Murdoch, based on a memoir by Murdoch's husband, John Bayley. The film won awards, but critics complained that it dwelt on the saddest and least productive period in Murdoch's life, when she struggled with Alzheimer's disease. Murdoch's own letters here in Living on Paper offer a more accurate portrait, both of a great literary and academic figure and of the woman behind the reputation.

The book's early sections are perhaps the most interesting. There is an excitement in reading the jottings of a young woman, already showing talent and chosen as head girl at her school, on the cusp of what would be a brilliant and vivid life.

Murdoch was born in Dublin in 1919, her family moved to England when she was a baby, and she won an exhibition to study at Somerville College, Oxford in 1938, graduating in the midst of World War II. It's perhaps unsurprising that she was precocious and articulate, writing in 1939 that she wanted to delve into "the origins of Greek religion and pursu[e] the labyrinthine paths of comparative mythology" before writing "a few poems, and publish a modest little novel now and then (maybe)."

In the same letter, she confides to her friend that her emotional life at Oxford gave her trouble, with "too many people" in love with her. "I find myself quite astonishingly interested in the opposite sex, and capable of being in love with about six men all at once." Later on, she would involve herself in various love triangles. In 1945 she was living with Michael Foot (an academic, not the politician) - a man she says she didn't love - only to have her attention diverted by Thomas Balogh, an economics don from Oxford. Her beloved female friend, Philippa, then fell in love with Michael, whom she would marry and who would leave her for his secretary a decade later. Writing to David Hicks (she would soon embark on a relationship with him), Murdoch notes, "It's a quadrilateral tale that would make rather a good psychological novel."

As these glimpses indicate, the letters shed most light on Murdoch's personal life, and when philosophy appears it's an anecdotal, occasional presence. The editors, Avril Horner and Anne Rowe, rightly point out that "few letters engage with philosophical ideas and theories in any depth; readers must turn back to her philosophy for that." What the letters do provide is an intensely personal insight into Murdoch's romances and friendships, and the whirlwind of social life that she maintained over decades.

There is something almost diary-like about these letters and something voyeuristic about reading them. It was an era when people wrote frequently, even daily, and when even the phone was viewed as a gadget. "Write me a long letter," Murdoch says to one friend. "Phone calls won't be enough." Letters take the place of personal meetings, and Murdoch tells Raymond Queneau-a French poet and novelist whom she loved unrequitedly-that "we shall be acquainted with each other only through letters."

Murdoch was, of course, a complicated person. She worried about her philosophical ability and complained about difficulties every time she wrote a book. On finishing The Sea, the Sea, which would win a Booker Prize, she described it as "an unusually troublesome novel." On a personal level, she was anxious about the prospect of marriage but also compelled by it, and had at least two engagements before meeting her husband. She also had a "very strong irrational fear of pregnancy." Politically, she was far left to begin, joining the Communist Party at university and spying for it during the war, copying papers from the Treasury and depositing them at Kensington Gardens. Later in life, she supported Britain's Labour Party but became disillusioned with it, hated Arthur Scargill and the unions, and ultimately turned, although with misgivings, towards Margaret Thatcher. "Maggie is a lot of good, and a lot of bad too," she wrote to an American friend. "I've met her briefly a few times and like her quite a lot, as well as, selectively, admiring her."

There is little in these letters to indicate that she felt a sense of struggle as a woman making her way in the world in the 20th century. During her phase frequenting the pubs of Soho after university, she notes that it was difficult "to cope with that sort of society and appear neither a whore nor a bluestocking." She admired Simone de Beauvoir, the French feminist, but had little time for what she described as "revolting women's studies."

Although her admirers were plentiful, she faced several rejections - by David Hicks, who broke off their youthful engagement, her beloved friend Raymond Queneau, and others - until meeting John Bayley at a party in 1954 (a time during which she was passionately involved with the author and theorist Elias Canetti). The letters' editors suggest that the relationship may have given her emotional security. Still, she continued to have numerous other affairs with both women and men - most notably with Brigid Brophy, an unconventional, polymathic woman, who was also herself already married.

How much do letters like these reveal about a writer? This collection is inevitably one-sided, and it often feels a pity not to have the responses, the absence of which leaves the conversation feeling incomplete, a monologue rather than the dialogue it really was. Murdoch herself felt the details of her life were irrelevant to an understanding of her work. But the letters do reveal how high-profile events can become almost ordinary - Murdoch remarking without fuss about a party at Number 10 (Downing Street) or a meeting with Enoch Powell, the Conservative politician. And they frequently also underscore the genius of their author. On a friend's depression, she observes, "How terribly odd the human mind is, so able to make its own heaven and hell."

The final letter included here is a poignant one, and ends with "please forgive all this stumbling." Knowing, as we now do, that Alzheimer's clouded her final years, this admission couldn't be more heart-breaking. And yet, this final section represents a very small part of Murdoch's life.

At the age of just 24, Murdoch wrote, "I want to write a long long and exceedingly obscure novel objectifying the queer conflicts I find within myself and observe in the characters of others." The letters go a way towards illuminating those queer conflicts.